2019 ASHS Annual Conference

Superficial scald (SS) is an important postharvest physiological disorder on pears (Pyrus communis L.), more so today with the ban of diphenylamine (DPA) and ethoxyquin residues on fruit in European markets, leaving the industry with few (or none) control treatment options. The symptoms include irregular brown patches on the skin that can darken and sunken in severe cases. In order to find a replacement for synthetic antioxidants, a search for a new natural product started in 2012, a combination of plant-extracted oils and emulsifiers were evaluated on Packham’s Triumph pears. Fruit quality (external appearance, firmness, soluble solids, ethylene production) and SS incidence during cold storage (up to 210 days, -0.5°C, >90% RH) were assessed under laboratory and semi-commercial conditions. After the first 3 years, we selected 4 prototypes based on their level of phytotoxicity on the fruit as well as efficacy. In the next 3 years we also included dose-response experiments. Final formulations at 1% (v/v) drenched at harvest have shown efficacy levels >80%, and significantly (P≤0.05) greener and firmer fruit throughout the storage period compare to the untreated control and DPA-treated fruit.